In the example described in document FR-2,811,395, this type of vehicle comprises a speed transmission device with a motive primary line arranged substantially parallel to a driven secondary line that controls the drive wheels of this vehicle. The primary line consists, on the one hand, of a main drive shaft driven in rotation by the thermal engine through a disengaging coupling and, on the other hand, of a tubular auxiliary drive shaft driven in rotation by the electric motor and surrounding the main drive shaft. The main drive shaft and the auxiliary drive shaft can be rotatingly secured to one another by a jaw clutch. Each shaft fixedly carries two toothed wheels interlocked each with driven toothed wheels carried by the driven secondary line while being mounted idle on this line. This line also carries alternate-clearance sliding gears allowing to rotatingly secure the driven toothed wheels to this secondary line.
Thus, during operation, the vehicle is driven into motion at different speeds, either by the electric motor or by the thermal engine, or by both. This is achieved by acting upon the various couplings (disengaging coupling and/or jaw clutch and/or sliding gears) carried by the different lines in order to secure the main drive shaft to the thermal engine and/or this main drive shaft to the auxiliary drive shaft and/or one of the driven toothed wheels to the driven secondary line.
Although satisfactory, this transmission device however involves some significant drawbacks.
In fact, when only the electric motor is used to drive the vehicle, it is necessary to couple the driven wheel to the secondary line so as to transmit the rotating motion of this electric motor to this secondary line. This involves device complexity in order to fulfill a basic function.
Furthermore, the vehicle must comprise a multiplicity of actuators for controlling the disengaging coupling, the jaw clutch and the sliding gears. These actuators increase the device production cost and they can be the source of failures and/or malfunction.
Besides, these actuators must be controlled by a processing unit such as the calculator the engine is usually provided with, which requires increasing the capacity of this calculator.
Finally, it is necessary, in order to obtain the desired speed, to couple or to uncouple some elements of the device, such as the driven toothed wheels. This has the effect of extending the time required for shifting gears while involving driving discomfort.
The present invention aims to overcome the aforementioned drawbacks by means of a simple and inexpensive speed transmission device.
Furthermore, such a device allows to use independently either engine while enabling energy recovery upon deceleration of the vehicle.